A promissory note is a written promise by one party to pay another party a specified sum of money either on demand or at a specified future date. It is commonly used in business as a means of short-term financing.For example, when a company has sold many products but not yet collected payments for them, it may become low on cash and unable to pay its own creditors with cash. In this case, it may ask its creditors to accept a promissory note that can be exchanged for cash at a future time after it collects its accounts receivables. Alternatively, it may ask the bank for the cash in exchange for a promissory note to be paid back in the future. Promissory notes lie between the informality of an IOU and the legal rigidity of a loan contract.  A promissory note generally contains all the terms relevant to the indebtedness, such as the amount, interest rate, maturity date, date and place of issuance, and issuer's signature. It is usually held by the party that is owed money, and returned to the issuer when payment is made. It does not usually explain methods of recourse if the issuer does not pay on time. When such a note is unconditional and saleable, it may be sold as a financial instrument. These are often called negotiable instruments.